The metaphor is perfectly adapt since the proposition of this thread is not "what if bayonets suddently became widespread earlier?" It is, once again "what if bayonet was invented earlier". What would be the implications and effects?
Now it's fair to say that it may not catch on for various technical reasons (of which none proposed so far seems convincing), but to say that it couldn't catch on simply because it wasn't invented earlier or that there were (inferior) alternatives is tantamount to saying the sandwich couldn't catch on if invented earlier because people had other things to eat.
No, its not. There is no reason for it to be invented earlier with any impact large enough to notice unless and until the problems you are determined to ignore are addressed.
So except for the ubergeeky who think *insert name *here** inventing the bayonet in *insert year* is cool, the bayonet being invented earlier has no real impact. And speaking as someone who is on the fifth step for a twelve step program for that, that's really, really minor.
The sandwich doesn't take any developments of slabs o' meat - instead of getting your hands greasy, you put your slab of meat between two pieces of bread. The bayonet not being anything other than a flash in the pan does require a change to existing weapons, tactics, and so on. And there's no reason it will inspire them on its own. Now if matchlock + bayonet was somehow superior, then maybe people would act accordingly. But it isn't - its less effective vs. cavalry and more awkward and unwieldy in general than the other "white weapons".
Your claim that matchlock and bayonet would be inferior to rapier needs further proof that your saying so. How is it inferior? Was the matchlock too heavy? Then why did the plug bayonet and early heavy flintlock combo catch on?
Because the flintlock
isn't as heavy and unwieldy as the matchlock?
Though some matchlocks were heavy, there were also light and handy matchlocks. If the bayonet was invented, it seems logical matchlock makers would gravitate toward the lighter variety than to simply abandon the bayonet.
It seems logical only if you think the bayonet is going to somehow make up for the fact the pike does the job it is supposed to do better in the first place. And the matchlock does not produce sufficient, effective firepower to justify relying on firepower - so we go back to you ignoring what everyone else has been saying.
Meanwhile, the light and handy matchlocks aren't the ones used by standard infantry - i.e., the ones which are going to be using the bayonet.
No one deliberately used the heavy form just to frustrate bayonet lovers.